This is a note to let you know that I've just added the patch titled
ACPI / processor: Avoid reserving IO regions too early
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: acpi-processor-avoid-reserving-io-regions-too-early.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From 86314751c7945fa0c67f459beeda2e7c610ca429 Mon Sep 17 00:00:00 2001
From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com Date: Thu, 2 Jun 2016 01:57:50 +0200 Subject: ACPI / processor: Avoid reserving IO regions too early
From: Rafael J. Wysocki rafael.j.wysocki@intel.com
commit 86314751c7945fa0c67f459beeda2e7c610ca429 upstream.
Roland Dreier reports that one of his systems cannot boot because of the changes made by commit ac212b6980d8 (ACPI / processor: Use common hotplug infrastructure).
The problematic part of it is the request_region() call in acpi_processor_get_info() that used to run at module init time before the above commit and now it runs much earlier. Unfortunately, the region(s) reserved by it fall into a range the PCI subsystem attempts to reserve for AHCI IO BARs. As a result, the PCI reservation fails and AHCI doesn't work, while previously the PCI reservation would be made before acpi_processor_get_info() and it would succeed.
That request_region() call, however, was overlooked by commit ac212b6980d8, as it is not necessary for the enumeration of the processors. It only is needed when the ACPI processor driver actually attempts to handle them which doesn't happen before loading the ACPI processor driver module. Therefore that call should have been moved from acpi_processor_get_info() into that module.
Address the problem by moving the request_region() call in question out of acpi_processor_get_info() and use the observation that the region reserved by it is only needed if the FADT-based CPU throttling method is going to be used, which means that it should be sufficient to invoke it from acpi_processor_get_throttling_fadt().
Fixes: ac212b6980d8 (ACPI / processor: Use common hotplug infrastructure) Reported-by: Roland Dreier roland@purestorage.com Tested-by: Roland Dreier roland@purestorage.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Acked-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/acpi/acpi_processor.c | 9 --------- drivers/acpi/processor_throttling.c | 9 +++++++++ 2 files changed, 9 insertions(+), 9 deletions(-)
--- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -331,15 +331,6 @@ static int acpi_processor_get_info(struc pr->throttling.duty_width = acpi_gbl_FADT.duty_width;
pr->pblk = object.processor.pblk_address; - - /* - * We don't care about error returns - we just try to mark - * these reserved so that nobody else is confused into thinking - * that this region might be unused.. - * - * (In particular, allocating the IO range for Cardbus) - */ - request_region(pr->throttling.address, 6, "ACPI CPU throttle"); }
/* --- a/drivers/acpi/processor_throttling.c +++ b/drivers/acpi/processor_throttling.c @@ -676,6 +676,15 @@ static int acpi_processor_get_throttling if (!pr->flags.throttling) return -ENODEV;
+ /* + * We don't care about error returns - we just try to mark + * these reserved so that nobody else is confused into thinking + * that this region might be unused.. + * + * (In particular, allocating the IO range for Cardbus) + */ + request_region(pr->throttling.address, 6, "ACPI CPU throttle"); + pr->throttling.state = 0;
duty_mask = pr->throttling.state_count - 1;
Patches currently in stable-queue which might be from rafael.j.wysocki@intel.com are
queue-4.4/pm-sleep-declare-__tracedata-symbols-as-char-rather-than-char.patch queue-4.4/acpi-processor-avoid-reserving-io-regions-too-early.patch queue-4.4/x86-cpu-intel-introduce-macros-for-intel-family-numbers.patch queue-4.4/acpica-namespace-fix-operand-cache-leak.patch queue-4.4/acpi-scan-prefer-devices-without-_hid-_cid-for-_adr-matching.patch